Fuckin awesome bro! I love it!
this is the F1 right? what are your goals for the cross? What are the parent strains and do u have pics of the P1 mom and dad?
on to the question, The F1 will carry a homogeneous mix of the parent strains DNA so as long as you choose a good strong male and a few females you should be fine. I will say to put 2-3 males aside just in case 1 starts looking better than the others or one develops intersex traits that way you have backup, but still not so many you need to devote a whole separate room to them.
with populations under 1000 you really need to be careful with each and every selection if you use too many males you wont be able to see where traits are coming from in the progeny and it becomes sort of a crapshoot, thats why I use multiple females to 1 or 2 males each generation, label and keep very meticulous records.
Keep in mind that when attempting to increase uniformity the goal is to reduce phenotypic and genotypic variation among the population (the less gene donors the better) to the point of homozygosity, this will also make the IBL stable and a very useful breeding tool.
just my 2 cents