Another reason to put the frame on stands when removing an engine is so you don't get spring bounce. So the soonest the weight of the engine off of the frame, the front end is going to bounce up because it is no longer pushing down on the springs. You don't want to make that mistake and accidentally smash something into the windshield..., been there done that.
You can lengthen the arm by pulling it out and drilling another hole for the pin I've done that but you have to understand that now you have to counterweight the back of the hoist otherwise the back of the hoist is going to flip up. And as stated before you are extending the lever arm and adding more stress to the hoist. You have to do this very very very very very very very carefully, but I can be done.
The method I used, pull the arm out leaving at least 8 to 12 in inside the main tube. Use a sharpie to draw the circle. Put a cross in that circle finding center. Drill a pilot hole all the way through. It has to be square..., parallel & perpendicular. Then use your step bit to make the hole larger. Then from there do not use the pin that's supplied. Use a bolt that is either a half inch or 9/16 inch grade 8 bolt. Then lock that down so you actually have clamping force that is holding the outer tube with the inner tube together not slopping around.