Let us confer with the MasterMind of Mars, Ras Thavas, and consider the benefits of **polyploids** for an endeavor such as yours.

[Synthetic Men of Mars](http://gutenberg.net.au/ebooks01/0100231h.html#chap7)
>Ras Thavas led us to an enormous room where we beheld such a spectacle as probably never had been enacted elsewhere in the entire universe. In the center of the room was a huge tank about four feet high from which were emerging hideous monstrosities almost beyond the powers of human imagination to conceive; and surrounding the tank were a great number of hormad warriors with their officers, rushing upon the terrible creatures, overpowering and binding them, or destroying them if they were too malformed to function successfully as fighting men. At least fifty per centum of them had to be thus destroyed—fearful caricatures of life that were neither beast nor man. One was only a great mass of living flesh with an eye somewhere and a single hand. Another had developed with its arms and legs transposed, so that when it walked it was upside down with its head between its legs. The features of many were grotesquely misplaced. Noses, ears, eyes, mouths might be scattered indiscriminately anywhere over the surfaces of torso or limbs. These were all destroyed; only those were preserved which had two arms and legs and the facial features of which were somewhere upon the head. The nose might be under an ear and the mouth above the eyes, but if they could function appearance was of no importance.
>
>Ras Thavas viewed them with evident pride. "What do you think of them?" he asked The Warlord.



The production of your homunculi is a process that Ras Thavas would recognize.  Each homunculus starts with the haploid genome of a sperm, and then duplicates its genome again and again, becoming massively polyploid.  Polyploidy can lead to great increase in size and vitality as is seen in many cultivated fruits.

https://www.reddit.com/r/WTF/comments/1l8yir/so_we_got_these_monster_strawberries_today/

[![polyploid mutant strawberries][1]][1]

Polyploidy leading to grotesque phenotypic differences does not usually occur in whole chordate organisms.  But in nonreproductive cancer cells which parasitize the host, polyploidy can likewise produce size increase – and produce other characteristics including the sidestepping of genetic safeguards that produce cell senescence and mortality.

https://www.researchgate.net/publication/326188263_Polyploid_Giant_Cancer_Cells_PGCCs_The_Evil_Roots_of_Cancer




>4. WHAT ARE POLYPLOID GIANT CANCER CELLS (PGCCS)?  
>
>The  size of PGCCs  can  vary  significantly  and  be  as  large  as  10  to 20 times  as compared with that  of regular diploid cells depending  on the  content  of  the DNA and  the number  of nuclei  in the  cells.  Genetically,  the  DNA  content  in  these giant cells needs to be equal (4C) or greater than tetraploid (> 4C). Depending on the  tumor type or treatment, PGCCs can vary in numbers and generally increase with tumor stage, grade, and treatment [19].  Endoreplication provides  an efficient strategy for growth and development from plants to mammals. If energy sources are limited or if cells are in rapid growth, increasing the cell volume and DNA content without division is more advantageous [20]. Similarly, PGCCs have a distinct advantage over regular cancer cells in dealing with stresses and reproduction [3-4, 6-7].  Increasing  DNA  content  by  endoreplication  is  a widely utilized effective mechanism to sustain the mass production of proteins and for high metabolic activity necessary for  tumor  growth.

Your homunculi are polyploid monsters which sidestep self-destruction via well-timed magical intervention.  Despite this, half or more are patently unfit for your purposes (though potentially useful for others); fortunately these culls can be recycled for their raw materials in your growth vats.  What you have remaining are extremely variable in appearance and ability due to their mutational burdens. Some may require artificial sustenance of one form or another to compensate for their inborn deficiencies.  You have learned to recognize and meet these needs.  Some might just need dietary additions of one sort or another, or a periodic return to the vat for renewal.  Some you can sustain with mechanicomagical prostheses.  Some might just have a very short life expectancy.  

The phenotypes of these homunculi are greatly dependent on the genotype of their “father” – all mammal males can be used to produce homunculi of some sort, but the ability to produce useful homunculi will greatly vary from one male to the next.  You are fortunate in that your own genetic code and idiosyncratic mutational burden confers a useful phenotype on your own homunculus “progeny”.  Homunculi produced by another male might be very, very different - but still possibly useful.  


  [1]: https://i.sstatic.net/DTxoX.jpg