Just practice, I am sure you will get the hang of it without messing around with tape etc
I have used DeVere enlargers professionally since 1972, and currently use the 10x8" with 5x4" and smaller inserts for smaller formats - The only trouble I have ever had is accurately locating 35mm negs for making large prints
However, I am shocked at the price, My current DV 5108E was Au$500 complete with lenses from 300mm to 50mm and all carriers, although I have replaced the 10x8" and 5x7" glasses, but normally I use the glassless carriers - In future I recommend you shop around and look at non-American countries where smaller formats are the norm